
  #include "stdio.h"
  #include "15topo.c"
  main()
  { int p[7], i;
    static int r1[8][2]={ {3,1},{3,2},{4,6},{4,7},
                          {5,4},{5,6},{5,7},{6,7}};
    static int r2[6][2]={ {3,1},{3,2},{2,7},
                          {4,5},{5,6},{6,4}};
    printf("\n");
    topo(7,r1,8,p);
    for (i=0; i<=6; i++) printf("%d  ",p[i]);
    printf("\n\n");
    topo(7,r2,6,p);
    for (i=0; i<=6; i++) printf("%d  ",p[i]);
    printf("\n\n");
  }

